New Proposed Category 11 heavy duty specification oils are on their way and before long will be in use at a fleet shop near you. Should fleets expect anything different in terms of oil and oil filter maintenance when they make the switch?

Yes, says Edward Covington, vice president of global quality for WIX Filters, at least theoretically, “but you’ll have to watch it.” He shares some considerations for fleets as the new-spec oils approach their market debut, which is now anticipated as early as December 2016.  

As a starting point, PC-11 oils are being designed to tougher standards, like higher shear and oxidation stability and better resistance to aeration, adhesion wear and thermal breakdown, Covington points out. The main drive to develop oils with upgraded performance is so they can maintain effective protection at lower viscosities in hotter-burning, more fuel-efficient, lower-emissions diesel engines on the way. Thinner viscosity oil means less resistance on the engines' moving parts, and thus less fuel that'll need to be burned to move them.

"What we've seen over time is that oils and filtration have improved along with engines as new specifications, technologies and additives have come out," Covington says. Oil filtering media also have evolved considerably over time to better protect against wear, he adds. "So generally, we expect that the new PC-11 oils are going to be more robust and resistant to breakdown," so the question is whether the oils, with proper filtration, will mean longer usable maintenance intervals. Covington notes that the oils' formulations are proprietary and still under development by a number of oil companies.

One of those is Chevron, whose Shawn Whitacre, senior engineer for engine oil technology, also recently became chairman of ASTM International's Heavy Duty Engine Oil Classification Panel. There, according to Whitacre, "We're responsible for establishing the spec itself — particularly the new tests and limits that will be associated with those tests, and incorporating that into the official ASTM spec that defines oil quality.

"The thinking of the industry is that these are going to be higher quality products than those they replace," he continues, agreeing that compared with the current CJ-4 heavy duty oils, "I think there's a lot of merit to the thought that these new oils will have the capability to go longer."

Ultimately, however, engine makers will have to make their own recommendations about oil and filter maintenance intervals with the new oils, Whitacre notes. "It's the OEMs' decision how they intend to leverage this expected performance improvement in terms of the recommendations they make for their new products," he says, "as well as for their existing and older products."

In addition to following OEM engine service recommendations, Covington suggests that fleets monitor and test their oil to determine what the optimal maintenance intervals should be for their specific engines, oil, fuel type and operating conditions. "If you look at it, some fleets are probably changing [trucks' oil and oil filters] too soon now and they could be going longer, and others are probably going too long now and they should be changing oil and filters more frequently," he contends.

Regardless of PC-11 oils' potential performance, Covington notes that environmental and operating conditions play a big role in (e.g., can shorten) usable oil life — things like lots of dust or moisture in the air or frequent stop-and-go traffic backups. "How and where a vehicle is being run is a significant part of it," he says.